Charles just moved to Echo City, and some of his new neighbors give him the creeps. They sneak into his room, steal his toys, and occasionally, they try to eat him. The place is teeming with monsters! Lucky for Charles, Echo City has Margo Maloo, monster mediator. No matter who’s causing trouble, Margo knows exactly what to do―the neighborhood kids say monsters are afraid of her. It's a good thing, because Echo City's trolls, ogres, and ghosts all have one thing in common: they don't like Charles very much.